Braxton hicks contractions?

So I’m 17 weeks 5 days and for the last 2 days I have felt like what feels like period cramps in my front and lower back. It happened 2 times yesterday and 2 times so far today. When I just felt it today I felt my belly and it was hard at the bottom until the cramps went away. It’s only like a min long. I have been drinking at least a 64oz bottle of water a day and I do not work only take care of my 2.5 year old and the house. So nothing crazy. Is it false contractions or something else? I never felt this with my first son. Also this baby is super low. Like I have a Doppler and I find him at my c section scar and that’s where I feel all the movements. My dr office just closed at 5pm and I don’t wanna worry myself until the morning and also don’t know if I should call a On-call nurse or got the ER to be checked out.